Light-sensitive photographic paper containing an ethenone material



y 1958 T. DAVIS ET AL, 2,835,578

LIGHT-SENSITIVE PHOTOGRAPHIC PAPER CONTAINING AN ETHENONE MATERIAL FiledOct. 31, 1955 PH 0 TOG'RAPH/C SILVER HA L IDE EMULSION BA R Y TA COAT/N6GELATIN AND KETENE D/MER PHOTOGRAPH/C SILVER HA LIDE EMULSION FigzPHOTOGRAPH/C GELATINO- SILVER HAL/DE EMULSION CONTAINING KETENE DIMER\GELATIN AND g- 3 KETENE DIMER GELATIN AND KETENE DIMER Kearney]?Eriffin TI; olpas L..D avis William Driscoll INVEN TORY OS MQh y n-Ton17$ United States Patent LIGHT-SENSITIVE PHOTOGRAPHIC PAPER CONTAININGAN ETHENONE MATERIAL Thomas L. Davis, William T. Driscoll, and KearneyP. Griflin, Rochester, N. Y., assignors to Eastman Kodak glompany,Rochester, N. Y., a corporation of New ersey Application October 31,1955, Serial No. 543,892 4 Claims. (Cl. 96-85) This invention concernsthe preparation of photographic paper, more particularly a photographicpaper having a surface that is resistant to the penetration of water andprocessing chemicals.

In the preparation of photographic paper, it is customary to coat thepaper with a baryta coating over which is coated a photographic emulsioncontaining gelatin and light-sensitive silver halide salts. However, inthe course of making photographic prints it is necessary to process thephotographic paper usually by immersing the paper in baths of processingsolutions. Extensive washing is required of these photographic papersafter processing to remove excess silver and silver complex salts. Suchchemicals, if retained in the paper, impart an objectional color orstain to the prints and affect the permanence of the paper. Theseconditions are undesirable especially where legal documents areinvolved.

In order to overcome the necessity for extensive washor in thealternative, staining, various coatings for photographic paper have beensuggested. For instance U. S. 2,415,631 issued to Galley teaches theformation of a water resistant photographic paper in which baryta coatedpaper is coated on both sides of the paper with a melt coating of alow-viscosity butyric acid ester of cellulose. The sensitized emulsionis applied on the baryta coated side of the paper over the butyric acidester.

For ordinary purposes, complete waterproofing of the paper is notnecessary, but it has been desired to provide a paper which would havereduced penetration of processing chemicals and the like, so that theWashing period might be reduced and the permanence of the paperimproved.

Various problems are introduced when sizing agents are used on the paperbase under a photographic emulsion such as emulsion frill in which theemulsion separates from the paper base particularly during processing.For this reason, many commercial sizes have been found unsuitable forphotographic paper. We have discovered that the use of an alkylketenedimer when prepared in a suitable solution can be used to protectphotographic paper base from penetration of processing chemicals and thelike. When used as a component of a paper sensitizing gelatino-silverhalide photographic emulsion, an improved bond between paper andemulsion is obtained, particularly when the paper has been treated witha gelatino-ketene dimer size.

One object of our invention is to-provide a simple and direct method ofpreparing photographic paper in which the paper support becomessemi-water resistant. Another object of our invention is to provide aphotographic paper which tends to restrict penetration into the paper ofprocessing chemicals and the like. A further object is to provide aprocess for improving the surface characteristices of photographic papersupports. An additional object is to provide a paper sizing materialwhich can be used with a photographic emulsion free from emulsion frill.Another object is to provide a sizing material which reacts withcellulose fibers on the surface ice 2 of the paper and becomes anintegral part of the paper. An additional object is to provide agelatino-photographic emulsion with improved adhesion when coated on apaper support. Other objects of our invention will appear herein.

Ketene dimers have been known in the art for use in treating variouscompounds. For instance, U. S. Patent 2,171,241, issued August 29, 1939,to Johnson discloses a process of modifying silk fibers by exposing thesilk fibers to the action of a ketene dimer. U. S. 2,383,863, issuedAugust 28, 1945, to Hueter teaches a process for preparing ketenedimers. Other disclosures show treatment for rendering textiles, fibers,and the like water repellent in which these materials are treated withhigher molecular ethenones or ketenes and subjected to a mild heattreatment.

The use of ketene dimers produced according to the Heuter process andused for producing water resistant paper, when coated with aphotographic emulsion, results in emulsion frill during the photographicdeveloping process. Consequently, it would be expected that the use ofketene dimers would not be applicable for photographic purposes.

We have found unexpectedly that we can prepare a sizing solution forphotographic applications which is compatible with photographicemulsions and which is free from emulsion frill duringphotographicprocessing. In our invention, we use an aqueous sizingsolution containing from 0.5 to 4%gelatin, and 0.6 to 3% of analkylketene dimer prepared according to the Heuter process.

Also included in the scope of our invention is the addition of stearoylhexadecyl ethenone to gelatin coating compositions which may containother materials. For instance, gelatino-silver halide photographicemulsions, dye containing compositions, and other gelatino coatingcompositions may have this material added thereto. This addition aids inthe bonding of these coatings to previous coatings containing stearoylhexadecyl ethenone in the event that the emulsion is coated on a supportcontaining stearoyl hexadecyl ethenone. When used on a paper which hasnot been so sized or over a baryta coating, an improved result is alsoobtained as compared to gelatinophotographic emulsions without stearoylhexadecyl ethenone. The emulsion containing stearoyl hexadecyl ethenonefiows onto the paper support with greater facility and results in a moreuniform product. From 6 to 35% of the ketene dimer is' incorporated intothe emulsion based on the weight of the gelatin in the emulsion.

The attached drawing illustrates photographic papers in accordance withour invention. Figure 1 shows a photographic paper having a barytacoating over the gelatino-ketene dimer size. Figure 2 shows aphotographic paper without the baryta coating, with the photographicemulsion coated directly on the gelatino-ketene dimer sized paper.Figure 3 shows a photographic paper coated with a gelatino-silver halidephotographic emulsion containing a ketene dimer.

The starting compound used to prepare the ketene dimer may be one ofthose disclosed by Heuter. However, we prefer to use the ketene dimersin which the starting material is stearic or lauric acid.

Preparation of the ketene dimer dispersion must be carried out undercarefully controlled conditions. We have found that the preferred methodof preparing a dispersion In preparing photographic paper according toour invention, the paper is sized by immersing it in a solution ofgelatin and ketene dimer although the sizing solution may be applied byconventional means such as dip roller, spray coater and the like.Following this operation, the paper is dried and sensitized by coatingwith a photographic emulsion containing light-sensitive silver halidesalts. In some grades of paper the paper is baryta coated and dried at atemperature of from ISO-250 F. followed by coating with a photographicemulsion containing light-sensitive silver halide salts.

In preparing gelatino-silver halide photographic emulsions containingstearoyl hexadecyl ethanone, the ketene dimer may be dispersed in wateras shown above for preparing a paper size. It may also be dispersed byheating in methanol, ethanol or the like to a temperature of from 115 to140 F., preferably to about 120 F. and then added directly to thegelatino-photographic emulsion which is usually at a temperature ofabove about 90 F.

The paper coating composition containing stearoyl hexadecyl ethenone ismaintained at a temperature of from 85-125 F. during the coatingoperation to obtain optimum results in coating and stability of thedisper- $1011.

The following examples illustrate our invention but are not intended tolimit it in any way.

Example 1 A gelatino-silver halide photographic emulsion was preparedfor sensitizing photographic paper base. Stearoyl hexadecyl ethenoneequal to 22.5% of the weight of the gelatin in the emulsion wasdispersed by heating 140 F. in 40% of its weight of methanol. Thisdispersion was added hot, directly to the photographic emulsion whichwas then coated in the normal manner on supports sized with compositionscontaining stearoyl hexadecyl ethenone. Other amounts of stearoylhexadecyl ethenone, including 34.75, 22.5, 12.25 and 6.1% based on theweight of gelatin, were also used. Good bonding was obtained between thesupport and the emulsion in all of the above applications.

Example 2 A 100% beaten rag fiber sheet was made containing rosin size,aluminum chloride, load (TiO melamine formaldehyde and heater gelatin.The paper was surface sized with a two bath operation containingstearoyl hexadecyl ethenone and 0.5% gelatin in the first pan and 1%gelatin in the second pan. Normal drying and calendering conditions wereobserved throughout the making.

Example 3 A 100% beaten rag fiber sheet was made containing aluminumchloride, load (TiO melamine formaldehyde, and beater gelatin. The paperwas surface sized with stearoyl hexadecyl ethenone and gelatin as shownin Example 2.

Example4 The same type of 100% beaten rag fiber sheet, chemicals andsurface sizing as described under Example 3 were used in preparingphotographic paper base which was coated with a baryta-gelatin coating.

Example 5 A 100% beaten rag fiber sheet was made containing rosin size,aluminum chloride, load (TiO melamine formaldehyde, and beater gelatin.The paper was surface sized with a one bath operation containingstearoyl hexadecyl ethenone and 2 to 4% gelatin.

Example 6 A 100% wood base sheet was made containing A-size, aluminiumchloride, melamine formaldehyde, starch, and beater gelatin. The paperwas surface sized with a one bath operation containing stearoylhexadecyl ethenone and 2 to 4% gelatin.

Example 7 A beaten wood base sheet was made containing A-size, aluminumchloride, load (TiO melamine formaldehyde, starch, and beater gelatin.The paper was surface sized with a one bath operation containingstearoyl hexadecyl ethenone and 2 to 4% gelatin.

Example 8 A 100% beaten wood base sheet was made containing aluminiumchloride, load (TiO melamine formaldehyde, starch, and heater gelatin,but no A-size. The paper was surface sized with a one bath operationcontaining stearoyl hexadecyl ethenone and 2 to 4% gelatin.

Example 9 A 100% wood base sheet was made containing aluminum chlorideand melamine formaldehyde. The paper was sized by various methods with asolution of stearoyl hexadecyl ethenone and /z% gelatin. The hopper,suction slide hopper, nip, and spray methods were all comparable to thesize press method previously described.

Example 10 A 100% wood base sheet was made containing A-size,hydrochloric .acid, melamine formaldehyde, beater gelatin, and starch.The paper was sized with a solution of stearoyl hexadecyl ethenone and/2 gelatin.

Samples of paper prepared according to the above nine examples werecoated with light-sensitive silver halide emulsions and processed inphotographic developing and fixing solutions. No emulsion frill waspresent. Similar samples sized with aqueous stearoyl hexadecyl ethe nonealone showed quite poor emulsion adhesion. The processed papers sizedwith stearoyl hexadecyl ethenone and gelatin showed 4050% less residualchemicals under similar processing conditions than paper base which hadnot been sized with the stearoyl hexadecyl ethenone gelatin mixture.This reduction in residual chemicals indicates that washing may beaccomplished in a much shorter time. The finished print on paper sizedwith the gelatin-stearoyl hexadecyl ethenone sizing had much lesstendency to stain than a print on regular stock which did not containthe stearoyl hexadecyl ethenone-gelatin sizing.

The stearoyl hexadecyl ethenone-gelatin sizing may be applied to rag orwood fiber by surface sizing, nip sizing or spray sizing. It may also beapplied to one side of the sheet to improve the coatability ofsubsequent applications such as baryta and the like.

In photographic processing of prints one of the time consuming stepsnormally present is that of washing the photographic prints to removeresidual chemicals such as silver and silver complexes which ifpermitted to remain will result in stains on the print. We havediscovered a size which may be used to coat photographic paper to renderit resistant to water and to processing chemicals and which, therefore,permits processing with a shorter washing time than was previouslypossible and yet obtain a suitable photographic print free from residualchemicals which might produce stain and the like. In addition, our sizehas the advantage over commercially available sizes in that it is freefrom emulsion frill during photographic processing.

Moreover, this sizing material provides a highly improved surface onwhich for some purposes may be deposited a photographic emulsiondirectly without requiring a baryta coating placed over the sized paper.Consequently, the use of our sizing material will serve to improvephotographic papers as will as save time and money for the photographicprocessors who will not now need to spend as much time in washing thephotographic prints.

This ketene dimer is compatible with photographic emulsions and. freefrom photographic activity. It not only can be used to size photographicpaper base, but also can be used as a component in photographic emul- 5sions. When used in a photographic emulsion it enhances adhesion to thepaper base and also improves the fiowability of the emulsion onto thepaper support and results in more uniform photographic paper.

We claim:

1. A photographic paper containing a coating from an aqueous solutioncomprising 0.5 to 4% gelatin and 0.6 to 3% of an ethenone materialhaving the following formula in which R is an alkyl group containingfrom 12 to 18 carbon atoms, coating with a mixture containing gelatinand baryta, and coating with a photographic emulsion containing lightsensitive silver halide salts.

3. A light sensitive gelatino-silved halide emulsion containing 635% ofstearoyl hexadecyl ethenone based on the weight of the gelatin in theemulsion.

4. A photographic paper containing a stearoyl hexa decylethenone-gelatin size in which from 0.15 to 3.0% of the dry weight ofthe uncoated paper is the ethenone and from 0.15 to 3.0% the dry weightof the uncoated paper is gelatin and having a light sensitive gelatinosilver halide emulsion.

References Cited in the file of this patent UNITED STATES PATENTS2,334,215 Nadeau et a1. Nov. 16, 1943 2,360,216 Fillius' Oct. 10, 19442,606,832 Alles et a1. Aug. 12, 1952 2,627,477 Downey Feb. 3, 1953

1. A PHOTOGRAPHIC PAPER CONTAINING A COATING FORM AN AQUEOUS COMPRISING0.5 TO 4% GELATIN AND 0.6 TO 3% OF AN ETHEONE MATERIAL HAVING THEFOLLOWING FORMULA